Senior Scientist, Inflammation & Chronic Disease
Ottawa Hospital Research Institute

Professor, Obstetrics & Gynecology
University of Ottawa

Professor, cross-appointed, Biochemistry, Microbiology & Immunology
University of Ottawa

A pill for advanced maternal-age infertility?
    Infertility has become an increasing social and medical issue as women delay childbearing in modern society. Declining egg quality is the most important factor in these reproductive difficulties. Our recent discovery offers a promising solution. We have identified putrescine deficiency as a major cause of poor egg quality in aged mice. Putrescine is a biogenic polyamine naturally produced in peri-ovulatory ovaries in all animal species studied thus far. Peri-ovulatory putrescine supplementation in drinking water reduces miscarriage and increases live births in aged mice. If similar strategy proves effective in women, peri-ovulatory putrescine supplementation may be the magic pill for millions of older women (i.e. 35 yrs. and older) pursuing healthy pregnancy.

Discovering the secret of cell division in the giant frog eggs     
    We have a longstanding interest in discovering the mechanisms of polar body formation during animal oocyte maturation, using Xenopus frogs as a model. Unlike a typical cell division producing two identical daughter cells, oocyte maturation produces a miniature, non-viable polar body and a mature egg. Polar body formation serves to halve chromosome number while preserving all nutrients in the mature egg. This is especially important for the frog since the egg provides all nutritional needs of post-fertilization embryonic development until the tadpole stage. The giant frog eggs offer unparalleled technical advantages for the many fundamental discoveries, by others and by us. These discoveries provide insight into how cell builds a bipolar spindle, what determines spindle positioning within the cell to ensure maximum retention of nutrients in the eggs, and how the spindle align chromosomes properly to ensure expelling exactly half of the chromosomes (in polar body) to prevent aneuploidy. Aneuploidy, or chromosome error, invariably results in early embryo demise or severe birth defects (e.g. Down syndrome).

    
    After completing his undergraduate degree in China (South China University of Agriculture), he moved to Canada for his MSc (Plant Science, Dr. JF Peterson as supervisor) and PhD (Biochemistry, Dr. Gordon Shore as supervisor) at McGill University. Following postdoctoral training in the lab of Dr. Tony Pawson of Toronto’s Mount Sinai Hospital, he joined OHRI (then known as Loeb Medical Research Institute) in 1993 as a scientist and assistant professor at the University of Ottawa. 

Major Awards
Michel Chrétien Researcher of the Year (2009)
Premier's Research Excellence Award (PREA) (2000-2005)
Medical Research Council (now CIHR) Scholarship (1995-2000)

Li R, Leblanc J, He K, and Liu XJ.  Spindle function in Xenopus oocytes involves possible nanodomain calcium signalling . Mol. Biol. Cell, 27:3273-3283 (2016)

Tao Y, Liu D, Mo G, Wang H, and Liu XJ. Peri-ovulatory putrescinesupplementation reduces embryoresorption in older mice. Human Reprod 30:1867-1875 (2015)

Tao Y, and Liu XJ. Deficiency of ovarian ornithine decarboxylase contributes to aging-related egg aneuploidy in mice. Aging Cell. 12:42-49 (2013).    

Shao H, Li R, Ma C, Chen E, and Liu XJ. Xenopus oocyte meiosis lacks spindle assembly checkpoint control. J. Cell Biol. 201:191-200 (2013).    

Zhang X, Ma C, Miller A, Arabi H, Bement WM, and Liu XJ. Polar body emission requires a RhoA contractile ring and Cdc42-mediated membrane protrusion. Developmental Cell 15:386-400 (2008).

Sheng Y, Tiberi M, Booth RA, Ma C, and Liu XJ. Regulation of Xenopus oocyte meiosis arrest by G protein βγ subunits.  Current Biology 11:405-416 (2001).

Bayaa M, Booth R, Sheng Y and Liu XJ. Progesterone-induced Xenopus oocyte maturation is mediated by the classical progesterone receptor. Proc. Natl. Acad. Sci. 97:12607-12612 (2000).

Aging; Cancer; Infertility; Maternal and fetal health; Pregnancy; Women's health

Basic research; Clinical research; Clinical trials; Disease models; Drug development; Translational research